1. Field of the Invention
The invention relates generally to a tire cord fabric, and more particularly to a tire cord fabric for vehicle tires, comprising a plurality of parallel warp threads and a plurality of weft threads interwoven with said warp threads.
2. Description of the Art
It is common to produce tire cord fabric such that the weft threads are endlessly woven into the fabric so that at the margins of the fabric the weft threads are folded back or returned in order to directly form the next weft. During the dipping treatment of the finished fabric the threads thereof are stretched. The stretching has the effect that first the so-called crimp of the warp threads is eliminated. As a result, the fabric becomes narrower and that the crimp of the weft threads is increased. By means of the width stretch rollers, prior art techniques have attempted to maintain the normal width of the cord fabrics during dipping. However, with such prior art methods, the continuous weft threads will, in the marginal areas of the fabric, contract the warp threads so that the fabric has a higher density in its marginal areas.
To avoid this effect it is known to use a cord fabric having no weft threads so that only the parallel warp threads are introduced into the dipping system. Also, it has been proposed to use plastically deformable weft threads which can be plastically extended to avoid the increased weft crimp.
In order that the undesired phenomenon occuring by the dipping operation with known tire cord fabrics cannot have negative effects on the tires produced with such cord fabric it is typically the present practice to cut off the marginal areas of the cord fabric after dipping and frictioning so that those areas of the cord fabric which have been shrunk during dipping, and which therefore have a higher warp density, are not present in the frictioned cord fabric. Thus, an evenly dipped cord fabric is obtained. However, by cutting off the marginal areas, material is lost.
Cutting the continuous weft threads at the marginal rims of the cord fabric before dipping the same to avoid increasing the warp density in the marginal areas of the fabric, does not solve the problem, since the ends of the cut weft threads will be withdrawn from the marginal areas due to the crimping which is increased by the dipping operation, so that the fabric loses in its marginal areas the stability. Accordingly, also in such case the marginal areas of the dipped fabric have to be cut off and disposed.
The present invention addresses the above shortcomings of the prior art by producing a tire cord fabric characterized by even and uniform properties over its entire width, after dipping, so that the entire width of the fabric can be used in the production of vehicle tires without the necessity to cut off any parts thereof.